CVE-2020-11934 Sandbox escape vulnerability via snapctl user-open (xdg-open)

2020-05-2200:00:00

canonical

www.cve.org

5.9 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality Impact

NONE

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N

6.3 Medium

AI Score

Confidence

High

0.0004 Low

EPSS

Percentile

12.7%

JSON

It was discovered that snapctl user-open allowed altering the $XDG_DATA_DIRS environment variable when calling the system xdg-open. OpenURL() in usersession/userd/launcher.go would alter $XDG_DATA_DIRS to append a path to a directory controlled by the calling snap. A malicious snap could exploit this to bypass intended access restrictions to control how the host system xdg-open script opens the URL and, for example, execute a script shipped with the snap without confinement. This issue did not affect Ubuntu Core systems. Fixed in snapd versions 2.45.1ubuntu0.2, 2.45.1+18.04.2 and 2.45.1+20.04.2.

CNA Affected

[
  {
    "product": "snapd",
    "vendor": "Canonical",
    "versions": [
      {
        "changes": [
          {
            "at": "2.45.1+18.04.2",
            "status": "unaffected"
          },
          {
            "at": "2.45.1+20.04.2",
            "status": "unaffected"
          }
        ],
        "lessThan": "2.45.1ubuntu0.2",
        "status": "affected",
        "version": "2.45.1",
        "versionType": "custom"
      }
    ]
  }
]